Display refrigerator including controls for the operation thereof



Nav. 4,- 1947. A R. E. DAvls 2,430,329

DISPLAY REFRIGERATR INCLUDING conTRoLs Fon 'rma OPERATION THEREOF FiledJuly 3o, 1945 2 sneets-sne'et 2 /M/En/roe."

:S K C/ ,g-- @www A Patented Nov. 4, 1947 2,430,329' UNITED STATESPATENT ori-'ics DISPLAY REFRIGEBATOB INCLUDING N- TROLS FOR THEOPERATION THEREOF Russell E. Davis, St. Louis, Mo., assigner toHuasman-Ligonier Company, St. Louis, Mo., a corf poration of DelawarevApplication July 30, 1945, Serial No. 607,8 11V `6 Claims. l

This invention relates to improvements, in refrigerated food displaycases of the kind shown in my copending application Serial No. 547,385wherein sub-zerou temperatures are maintained in the continuously openself-service food display chamber of the case by a closed thermosiphonsystem of refrigerated air produced by a. refrigerating circuitincluding expansion coils located in the display chamber and an upperchamber in communication therewith and a condensing unit common to bothexpansion coils, and the upper expansion coil is defrosted by anelectric heater which is turned on when the condensing unit stops and isturned ofi' when the condensing unit starts.

The present invention has for its principal objects to preserve all ofthe advantages of the above type of refrigerated display case and, atthe same time, provide for automatically turning on the defrostingheater and stopping the condensing unit at a predetermined time,eliminate the electrically operated refrigerant valve heretoforeemployed and attain other advantages hereinafter appearing. Theinvention consists in the refrigerated display case and in the parts andcombinations and arrangements of parts hereinafter described `andclaimed.

In the accompanying drawings which form a part of this specicaton andwherein like symbols refer to like parts wherever they occur,

Fig. 1 isa front elevational view of an opentop, self-servicerefrigerated display case embodying my invention,`

Fig. 2 is an enlarged vertical cross sectional view through said case inline 2-2 in Fig. 1; and

Fig. 3 is a diagrammatic View illustrating the refrigerating circuit andthe electric control circuit for said refrigerating circuit and thedefrosting heater therefor.

In the accompanying drawings my invention is shown embodied in anopen-top, self-service refrigerated display case of the type shown in mycopending application Serial No. 547,385, wherein the display casecomprises a top wall I, a bottom wall 2, a relatively high rear wall 3,a relatively low front wall 4 and end walls 5. As shown in the drawings,the top wall I extends from the rear wall 3 of the case and terminatesshort of the front wall 4 thereof in a depending baille or curtain wall6 that extends below the level of the top edge of the front wall 4. Theabove described arrangement of walls provides a lower food storage anddisplay chamber A with an access or reach-in opening `A1 in thetopthereof between the iront wall 4 and the baille wall 6, and an' upperchamber B communicating with the upper portion of said food chamberrearwardly of said access opening. As shown in the drawings, a sealedmulti-pane glass panel 4a constitutes the upper portion of the low frontwall `l of the case; and sector-shaped glass panels 5a constitute theupper portions of the end walls 5 of said case between said front walland thel baille wall 6. lA suitable light, such as fluorescent tubing1a, is mounted in a suitable wiring conduit, shade and reiiector 1,which is secured to the front face of the bafe wall 6 hush with theupper surface of the top wall I;-`and an inclined mirror 8 inclinesdownwardly and rearwardly :from said conduit to said baille wall.

The hereinbefore described display case is provided with a mechanicalrefrigerating apparatus of the compressor-condenser-expander type. Asillustrated in the diagram shown in Fig. 3, the refrigerating circuitcomprises a suitable condensing unit C, including the usual compressorIl and electric driving motor 9a, and driving belt connection 9btherebetween condenser Ill and liquid receiver II therefor. Therefrigerating circuit also includes a suitable heat exchanger I2, asuitable throttle or expansion valve i3, and evaporators or expanders inthe form of a iintype cooling coil I4 and a series oi plate type coolingcoils l5. The refrigerant ows from the compressor 9 to the receiver IIthrough the condenser IIl, thence from the receiver to the heatexchanger `I2 through a conduit I6, thence from the heat exchanger tothe expansion valve I3 through a conduit I8, thence from the expansionvalve to the iin coil I4 through a conduit Ilia, thence through aconduit lbto the plate coils I5 and connecting conduits i9 therefor andthence from the plate coils and through the heat exchanger back to thecompressor through a return conduit 2l. As shown in the drawings, the1in coil i4 is located in the upper portion of the rear upper chamber Bof the food case and extends longitudinally thereof suhstantially fromend to end thereof, while the plate coils I5 are mounted on edge in thecold storage food display chamber A in spaced apart relation 'so as toform bins 22 therein that preferably extend from front to backthereof.As shown in Fig. 2each of the plate coils I5 comprises a. sealed casingI5a containing a flat cooling coil ISU and a suitable eutecticsolutionI5c which surrounds said coil and has a relatively low freezing point.

Mounted in the rear upper chamber B of the case immediately below theiin coll ll therein are drains o r gutters 23 for receiving and carryingaway moisture that drips from said coil. The gutters 23 extendlongitudinally of the `iin coil from end to end thereof and kareinclined from one end to the other so as to discharge into a suitabledrain pan 24 mounted in said chamber below the discharge end of saidgutters. As shown in Fig. 2, a vertical bailleor partition wall 25extends from end to end of the upper chamber B of the case beneath thenn coil Il therein substantially midway between the rear wall 3 and thebaille wall 6 with its upper edge fixed to the under side of one of thegutters 23 and with its lower edge disposed in the lower display chamberA slightly below the level of the lower edge of said baille wall. Thepartition or baille wall divides the portion of the upper chamber belowthe iin coil Il therein into vertical front and rear flues 25 and 21,respectively. 'I'he rear upper chamber B is provided with means forrapidlyl defrosting the fin type cooling coil I4 therein, said meanscomprising an electric heater preferably in the form of electricresistance wires or cables 23 secured to the undersides of the gutters2l forreceiving the liquid condensate from said cooling coil.

As shown in Fig. 3, the compressor motor 9ais operated by a, 220 voltelectric circuit 23 which is normally opened and closed by a suitablethermostatic switch 3l having a feeler bulb 3| located in the lower fooddisplay chamber A adjacent to or in thermal contact with the plate coilsI5 therein. The defrosting heater 23 is operated by a normally open.110volt electric circuit 32. A time controlled switch D has a pair ofcontacts 33, 33a, which open and close one side of themotor circuit 23,and a pair of contacts 3l, 34a, which open and close the heater circuit32. The contacts 33 and 3l are fixed one on each side of a -hinged orpivoted arm'35 for movement therewith into and out of engagement withthe stationary contacts 33a and 34a respectively. A spring 36 yieldablyholds the contact 33 in engagement with the contact 33a, to therebyclose the motor circuit 25, and with the contact 3l out of engagementwith the contact 34a so as to open the heater circuit 32. Thus, thecontacts 33, 33a in the motor circuit 23 are closed when the contacts34, 33a,in the heater circuit 32 are open and vice versa.

The time switch D also includes electrically controlled mechanismadapted at a predetermined time to actuate the contact carrying lever 35to open the motor circuit 23 and close the heater circuit 32. 'I'hismechanism preferably comprises an electric clock 31, which is connectedthrough wires 33 to heater circuit 32 for continuous operation thereby,a shaft 39 driven by said clock, a driving disk III xed to said shaft,and an edge cam 4I xed to said driving disk and in continuous edgewisecontact with a laterally bent free end portion of the hinged contactcarrying arm 35 so as to operate said arm whenever the rise lla of saidcam moves into engagement with the laterally bent free end portion ofsaid arm. As shown in the drawings, the cam 4I is secured to the camdisk 4l by means of a screw 43 `which extends through an arcuate slot 42in said cam and is threaded into said disk, thus permitting saidrotational adjustment of said cam relative to said disk to vary the timeof operation of the switch D. The cam 4I makes one completerevo1ution,'say once every 24 hours; and the circumferential length ofthe rise lla of said cam determines the length of time that the contactarm 35 is held Ain motor circuit opening and heater circuit closingposition during each complete revolution of said cam. As shown in Fig. 3the time controlled switch D and the thermostatic Switch 3l may beenclosed in a common housing 4I.

v As indicated by the ilow arrows in Fig. 2, when n the 'r'efrigeratingcircuit is operating to reduce the display chamber temperature to thedesired subzero level there is a continuous circulation of refrigeratedair downwardly from the upper iin coil cooling unit Ilthrough the ue 21into the 4 lower display chamber A and a return iiow of said air fromsaid display chamber to said upper iin coil unit through the ue 25. Thebaille curtain wall 6 of the case extends below the level of the topedge of the front wall 4 thereof and thus permits the refrigerated airin the open top display chamber A to rise above the lower edge of saidcurtain wall and this height, plus the atmospheric pressure exerted onthe display space opening A1, balances the weight of the refrigeratedair in the sealed Space back of said curtain wall and forms in saidopening a layer 43 of stratified or dead insulating air which tends toprevent the escape of the refrigerated air therethrough.

When the refrigerating apparatus is operating, the motor circuit 23 isclosed by the thermostatic switch 33 and the time switch D and theheater circuit 32 is opened by said time switch, thus putting therefrigerating apparatus into operation zo and rendering the defrostingheater 28 inoperative. During the operation ofthe refrigeratingapparatus, liquid refrigerant passes from the liquid receiver II of thecondensing unit C through the conduit I5, heat exchanger I2, conduit I8,ex-

u pansion or throttle valve I3, conduit I8a into the upper iin type'expansion coil I3 and thence through the conduit Ib into the lower platetype expansion coils I5. The liquid refrigerant, after evaporating andabsorbing heat in the expansion o coils Il and I5 is then converted intovaporized refrigerant which is returned to the condensing unit C throughthe conduit 2|, heat exchanger' I2 and again converted into liquid formin said condensing unit and again returned to the receiver 35 I Ithereof.

When the temperature in the lower display chamber A of the case reachesa predetermined low level, the thermostatic switch 30 is opened,/thereby opening the motor circuit 29 and stopping the`condensing unit Cand the ow of refrigerant therefrom through the refrigerating system.JWhen the display chamber temperature rises a few degrees above thedesired predetermined low level, the thermostatic switch 30 again closesthe 45 motor circuit 29 and puts the refrigerating appaing can be setfor the most opportune time of the day or night. For instance, the timeswitch .may be set to bring about the defrosting in the early morninghours when the store is cool and there is no activity therein so as tominimize dangerous temperature fluctuation. When the time for defrostingarrives, the rise lla on the clock operated cam 4I moves into engagementwith the free end of the contact carrying arm 35 and operates the latteragainst the tension of the spring 36, thus separating the contacts 33,33a and rendering the refrigerating apparatus inoperative and engagingthe contacts 34', 34a and Vstarting the defrosting heater 28..- The risella of the cam 4I remains in contact with the contact carrying lever 35for a period of time sumwill engage the contacts 33, 33a and again placethe thermostatic switch 30 and disengage the f contacts 34, 34a and cutolf the'defrosting heater.

An important advantage of the above described arrangement is that iteliminates the electrically operated valve heretofore used in the liquidline ofthe refrigerating system and renders the refrigerating systemdirectly responsive to temperaturerequirements in the food display'chamiber. Another advantage is that it eliminates the numerous temperatureiluctuations which occur when the defrosting heater is turned on duringeach cycleof the refrigerating system and thus prevents the displaychamber frombeing subjected to abnormal temperatures during eachrefrigerating cycle. V

Obviously, the hereinbefore described open-top self-service lowtemperature refrigerating display case admits of considerablemodification without departingfrom the invention. Therefore, I do notwish to be limited to the precise arrange-' ments shown and described.

What I claim is:

1. A refrigerated display case having a food chamber and a secondchamber in continuous communication therewith, and acompressorcondenser-expander type refrigerating apparatus including anelectric motor for operatingv the compressor, anexpansion coil in saidfood chamber and an expansion coil in said second chamber, an electriccontrol circuit for said motor including a thermostatic switchresponsive to temperature conditions in said food chamber only forstarting and stopping said motor, an electric heater in said secondchamber for defrosting the expansion coil therein, an electric controlcircuit for said heater, and a time switch associatedy with V 4. Arefrigerated display case having a food chamber and a second chamber incontinuous communication therewith, and a refrigerating apparatus' ofthe compressor-condenser-expander type including an electric motor foroperating the compressonan expansion coil in said food chamber andanexpansion coil in said second chamber, an electric control circuitfor/,said motor including a thermostatic switch responsive totemperature conditions in said food chamber only for both starting 'andstopping said motor, an electric control circuit for said heater, and atime controlled. switch associated with both circuits for opening themotor circuit and `closing the heater circuit at predetermined times.

5. AA refrigerated display case having a food chamber and a secondchamber communicating therewith, and a refrigerating apparatus of thecompressor-condenser-expander type including an electric motor foroperating the compressor,

an expansion coilin said food chamber and an Y expansion coil insaidsecond chamber, an electric control circuit for said motor including athermostatic switch responsive to temperature in rsaid heater circuit,and time controlled means said motor and heater circuits for openingsaid motor circuit and closing said heater circuit and vice versa atpredetermined times.

2. A refrigerated display case having a lower food chamber with acontinuously open access opening in the top thereof and an upper chamberin continuous communication with said lower chamber below the topthereof and rearwardly of the access opening therein, and acompressorcondenser-expander type refrigerating apparatus including amotor for operating the compressor, a iin-type expansion coil in saidupper chamber and a plurality of plate-type expansion coils ar- 'ranged'in spaced relation in said lowerchamber.

to form bins therein, an electric heater in said upper chamber fordefrosting the expansion coil therein, an electric control circuit forsaid motor including a thermostatic switchl responsive to temperatureconditions in said lowerv chamber only for starting and stopping saidmotor, an electric control circuit for said heater, and a timecontrolled switch associatedwith both circuits and -operable atpredetermined times to close 'said heater circuit and open said motorcircuitand viceversa. l

3. A refrigerated case. having two communicating chambers and asinglerefrigerating apparatus including expansion coils in the respectivechambers, control means responsive to temperature conditions inonechamber only for both starting and stopping the' operation of saidrefrigerating apparatus, a heaterfordefrosting the expansion coil inthe, other of said chambers, and means operable at predetermined timesfor turningon said heater and for preventing the starting of saidrefrigerating apparatus by said temperature responsive control means.

` Number Name Date 2,073,008 v Haschke Maxz 9, 1937 2,196,291 Clancy .lApr. 9, 1940 for'openingthe contacts in said motor circuit and forclosing the contacts in said heater circuit.

6. A refrigerated display case having a food chamber and a secondchamber communicating ltherewith, and a refrigerating apparatus of thecompressor-condenser-expander type including an electric mot'or foroperating the compressor,VV

'mostatic switch responsive to temperature con-- 45- ditions in saidVfood chamber only for both starting and stopping said motor, an`electric control circuit for said heater, and a switch associated withboth circuits for opening the motor circuit and closing the heatercircuit at predeterminedtimes, said switch including a pair of normallyclosed contacts located in said motor circuit, a pair of normally opencontacts disposed in said heater circuit, and time controlled means foropening the contacts in said motorcircuit and closing the contacts insaid heater circuit, said lastmentioned means comprising a pivotal armsupporting onevoi" the contacts of each pair for movement into and outof engagement with the other contact thereof, a rotary cam for actuatingsaid arm, and an electric clock for rotating said cam.

RUSSELL E. DAVIS.

REFERENCES CITED The following references are of record in the ille ofthis patent:

UNITED STATES PA'I'ENTS 2,327,355 Kleist Aug. 24, 1943

